Conventional screw and mechanical operated beds are adjustable to provide contoured support for a person resting thereon. However, these beds are high in cost and commonly are relatively heavy. Also, conventional mechanical adjustable beds are slow in operation and difficult to service.
In the past, beds have used inflatable bodies to elevate whole or selected portions of the mattress of the bed. For example, U.S. Pat. No. 2,769,182 issued to E. J. Nunlist on Nov. 6, 1956, discloses a bed having inflatable air cylinders for lifting the mattress of the bed. A pump driven by an electric motor delivers air under pressure to the air cylinders. A valve allows the person to inflate both of the cylinders or only one of the cylinders. The air cylinders can inadvertently move out of position whereby elevation and support of the mattress is uneven and unstable.